WASHINGTON — The U.S. Defense Department has selected some of the instruments that will fly on its new weather satellite system, but Congress will have to wait until August for more information on the platform that will host the sensors and on the program’s estimated cost, a Pentagon official told lawmakers June 29.

The first of the U.S. Air Force’s planned Defense Weather Satellite System spacecraft will be ready for launch by 2018 and will meet or exceed the capabilities of current U.S. military weather satellites, said Gil Klinger, director of the space and intelligence office within the Office of the Undersecretary of Defense for Acquisition, Technology & Logistics.

Klinger and officials from the U.S. National Oceanic and Atmospheric Administration (NOAA) and NASA had been called to testify before the House Science and Technology subcommittee on investigations and oversight on their latest weather satellite plans. For the last decade, the three agencies were working together on the joint civil-military National Polar-orbiting Operational Environmental Satellite System (NPOESS), but the White House ended that program in February and directed the Pentagon and civilian agencies to pursue separate systems.

The new military system will include two instrument packages originally planned for NPOESS: the Visible Infrared Imager Radiometer Suite and the Space Environmental Monitoring sensor, Klinger said. It will also carry a to-be-determined microwave sensor. The Air Force expects to spend $5 billion on the program through 2015.

The Air Force has not decided which satellite platform to use or estimated the total cost to complete the program, Klinger said. A full acquisition strategy will be complete by Aug. 10, he said.

Meanwhile, NOAA has informed Congress of some major decisions related to its new weather constellation, the Joint Polar Satellite System, which is being procured by NASA. The agency previously announced that the system’s first satellite will carry the same five instruments as a satellite known as the NPOESS Preparatory Project, which was originally intended as a test bed for NPOESS instruments but has been thrust into an operational role due to NPOESS delays. The NPOESS Preparatory Project satellite, built by Ball Aerospace & Technologies Corp. of Boulder, Colo., is scheduled to launch next year.

NOAA confirmed June 25 it would tap Ball Aerospace to provide the platform for the first Joint Polar Satellite System craft, scheduled for launch in 2014. The agency has not yet decided on a satellite platform or instrument package that will fly on the second Joint Polar Satellite System craft, targeted for launch in 2018, Mary Kicza, head of NOAA’s satellite operating division, told reporters during a June 28 conference call.

A complete plan for the Joint Polar Satellite System will be available by the end of the year, Kicza told lawmakers. The program is expected to cost a total of $11.9 billion through 2024, including the $2.9 billion NOAA has already spent on NPOESS.

A big question facing the Air Force and NOAA is what to do with the NPOESS prime contract held by Northrop Grumman Aerospace Systems of Los Angeles. Klinger revealed that the government would be liable for $84 million in termination fees if the contract is canceled, but he said that decision has not been made and is not desirable. Northrop Grumman’s NPOESS responsibilities included building the satellite platforms, managing development of the instruments and ground segment by subcontractors and integrating the overall system. The civil weather satellite system will utilize the NPOESS instruments and ground segment, with NASA responsible for procurement and overall system integration.

Both the Air Force and NOAA have indicated a desire to keep Northrop Grumman involved with their respective weather satellite programs, but the role the company would play is not clear. Ball Aerospace was selected to build the first Joint Polar Satellite System platform because it was deemed best able to meet the program schedule based on NPOESS Preparatory Project work, which included instrument integration. Northrop Grumman believes it could have provided a suitable satellite platform in time.

“Northrop Grumman has the Class A spacecraft ready for manufacturing, with key flight components built,” company spokesman Lon Rains said in a June 30 e-mail. “Northrop Grumman is already testing components on the spacecraft engineering test bed, with 100 percent of long lead items delivered from established supply chain. The spacecraft development continues to advance beyond the mission critical design review held in 2009 and is on a path to meet a launch readiness date in 2014.”

For the second Joint Polar Satellite System spacecraft, NOAA plans to include the five instruments manifested on the first satellite plus as many as three others: the Total Solar Irradiance Sensor; the Search And Rescue Satellite Aided Tracking instrument; and the Advanced Data Collection System. NOAA is committed to fielding these capabilities and will pursue other options, including international partnerships and dedicated satellites, if these instruments are not made a part of the Joint Polar Satellite System, Kicza told lawmakers.

Northrop Grumman’s satellite platform is capable of supporting all of the payloads under consideration by NOAA, Rains said.

Ball Aerospace believes its satellite platform could be modified at a “modest cost” to incorporate the Search And Rescue Satellite Aided Tracking instrument and Advanced Data Collection System, company spokeswoman Roz Brown said in a June 30 e-mail. Ball Aerospace has not studied the possibility of incorporating the Total Solar Irradiance Sensor, she said.